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A new series of anionic surfactants with dual type of activity antimicrobial and surface activity have been synthesized by reaction of 4H‐3,1‐benzoxazinone 3 and quinazolinethione 10 with nitrogen nucleophiles and activated olefinic compounds. The compounds were evaluated for their surface activity as well as their antimicrobial and biodegradability properties.

In the present investigation novel nonionic surfactants were synthesized, characterized and tested as inhibitors of the corrosion of carbon steel in 1M HCl solution. The inhibition action of these surfactants was studied by weight loss, galvanostatic polarization and electrochemical impedance spectroscopy. The adsorption of the inhibitors was well described by the Langmuir adsorption isotherm and the adsorption isotherm parameters were determined at different temperatures. The inhibition efficiency was found to rise when increasing the concentration of these compounds and decreasing the temperature. The effect of temperature on the inhibition efficiency of the corrosion process was studied and the values of some activated thermodynamic parameters were calculated to elaborate the mechanism of inhibition. The synthesized nonionic surfactants exhibit good surface and antimicrobial properties.

Síntesis y propiedades antibacterianas y tensoactivas de derivados 1,2,4-triazólicos Es interesante el uso del 1-(4-amino-5-mercapto-4H-[1,2,4]triazol-3-il)heptadecano-1-sulfonato sódico (2) como un nuevo precursor en la síntesis de compuestos heterocíclicos biológicamente importantes. La reacción de 2 con disulfuro de carbono en piridina y cloruros de acilo rindió derivados 1,2,4-triazólicos. Condensación de 2 con aldehídos apropiados produjo 5a-c que ciclaron por tratamiento con ácido tioglicólico para dar lugar a 6a-c. Reacciones de 2 con anhídrido ftálico y cloruro de 4-metilbenzenosulfonilo produjeron 7 y 8. Además, la reacción de 2 con cloroacetaldehído, bromuro de fenacilo, urea, cloruro de tiacetilo produjo 9, 10, 11, y 12. Por otra parte, el reflujo de 2 con isocianato de fenilo dio 13 y 14. Todos los productos tuvieron actividad antimicrobiana y propiedades tensoactivas.

RESUMENPropiedades tensoactivas y actividad biológica de nuevos surfactantes no iónicos conteniendo pirimidinas y anillos nitrogenados relacionados.Una serie de derivados pirimidínicos y relacionados han sido preparados vía diferentes reacciones de formación de heterociclos entre 6-(4-octadeciloxifenil)-4-oxo-2-tioxo-1,2,3,4-tetrahidropirimidina-5-carbonitrilo (4) y diferentes electrófilos y nucleófilos. Estos heterociclos tienen un átomo de hidrógeno activo (NH, OH, o COOH) que fue propoxilado con diferentes moles de óxido de propileno (5, 10, o 15) para producir surfactantes no iónicos con una cadena alquílica larga y peso molecular apropiado para convertirse en una molécula anfifílica con un balance hidrofílico-lipofílico correcto que aumenta la solubilidad y la biodedradabilidad, decrece la toxicidad a los seres humanos, y se convierte en respetuoso con el medio ambiente. Además, las actividades antimicrobianas de estos compuestos fueron determinadas y se encontró que algunos de estos compuestos tuvieron una actividad similar o más alta que antibióticos comerciales (sulfadiazina), lo que los hace apropiados para aplicaciones diversas como la manufactura de medicamentos, pesticidas, emulsificantes, cosméticos, etc. PALABRAS-CLAVE: Síntesis -Propiedades tensoactivas -Actividad antimicrobiana SUMMARY Surface active properties and biological activity of novel nonionic surfactants containing pyrimidines and related nitrogen heterocyclic ring systems.A series of annelated pyrimidine derivatives has been synthesized via different heterocyclization reactions of suitably functionalized 6-(4-octadecyloxyphenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile (4) with different electrophiles and nucleophiles. These heterocycles bear an active hydrogen atom (NH, OH or COOH) which could be propoxylated using propylene oxide with different moles, 5, 10 and 15, to produce nonionic surfactant having a long alkyl chain with molecular weight suitable for becoming an amphiphilic molecule with correct hydrophilic-lypophilic balance which enhances solubility, biodegradability and hence lowers the toxicity to human beings and becomes environmentally friendly. In addition, the antimicrobial activities of these compounds were screened and it was found that some of these compounds have similar or higher activity compared with commercial antibiotic drugs (sulphadiazine), which make them suitable for diverse applications like the manufacturing of drugs, pesticides, emulsifiers, cosmetics, etc.

The synthesis of water-soluble heterocyclic compounds was verified on the basis of nonionic surfactants for use as surface-active agents. Surface characteristics such as surface and interfacial tensions, cloud point, wetting time, emulsion stability, foaming height and foaming stability were measured for these surface factors in aqueous solutions. In addition, the critical micelle concentration (CMC), the surface pressure at CMC (π), the effectiveness of surface tension reduction (pC), the maximum surface concentration (Γ) and the minimum area/molecule at the aqueous solution/air interface (A) were calculated. Moreover, the biodegradability for these nonionic surfactants has been investigated. Furthermore, the antimicrobial evaluation has been evaluated with some surfactants that have demonstrated a potent cytotoxicity as antibacterial, antifungal and anticancer. These surfactants have a good water solubility, low toxicity, environmentally friendly environment, high foam, good emulsifier and easy production that will be used them in various fields such as medical drugs, insecticides, detergents, emulsifiers, cosmetics, inks clothing, leather industry and oil recovery.

The motivation behind the present work is to synthesize some nonionic surfactants containing heterocyclic nucleus with intermediate fatty compounds for improving their surfactants properties. 2‐Cyano‐N‐octadecylacetamide was utilized as key intermediate for the synthesis of some new thiazole, pyrazole, oxazole, pyrimidine, 1,3‐dithiolane, thiophene, coumarin, oxazine and pyridazine derivatives. The newly synthesized compounds undergo propoxylation using propylene oxide to afford nonionic surface active agents. The antimicrobial and surface activities were evaluated and characterized through investigations of their spreading behavior in monolayer on water.